The United Kingdom's nuclear weapons arsenal is crucially dependent on U.S. actions, as a key bilateral agreement is up for renewal, reports the London Guardian.
At issue is the so-called Mutual Defense Agreement, first signed in 1958. Work on the latest extension of the pact was ongoing on both sides of the Atlantic as of earlier this year, according to the newspaper's Defence and Security Blog. The agreement is key because it enables the British military to take advantage of nuclear-weapons work conducted in the United States, including the sharing of data, test results and the use of U.S. test facilities.
British politicians have previously assured the public that the country's stockpile of Trident warheads is reliable for another two decades or so. However, the blog quotes a Royal United Services Institute report concluding that "a limited understanding of warhead aging" makes precise estimates difficult.
In essence, the U.K. arsenal "will depend more upon external rather than internal factors," the London-based think tank's analysis concludes.
"Chief amongst these external factors will be the U.S. warhead program, which provides many key components of the U.K. arsenal," according to the think tank.
In other words, how the U.S. nuclear complex proceeds in maintaining and modernizing Washington's arsenal could affect the U.K. deterrent force.
"The U.K. may have no more luck predicting the future of the U.S. program than it does the reliability of its own arsenal," the think tank report reads. "The U.S. program is currently in flux, and is likely to remain so for the foreseeable future."
Replacing the warheads would take roughly 17 years and cost the equivalent of approximately $6.65 billion at today's prices, according to the Guardian article. Britain plans to reduce its stockpile of 225 Trident warheads to 180 or less, with up to 120 operationally available for the country's Vanguard submarine fleet, the blog quotes a 2010 Strategic Defence and Security Review as saying.